A program has been established for DOE Environmental Restoration and Waste Management (EM) to evaluate factors that are likely to affect waste glass reaction ,during repository disposal, with emphasis on an unsaturated environment typical of what may be expected for the proposed Yucca Mountain repository site. This report covers progress in FY 1991 on the following tasks: 11 A critic_ review of those parameters that affect the reactivity of glass in an unsaturated environment is in progress. This effort involves a search of the literature to identify the important parameters. Temperature and glass compositions are the first parameters examined in detail. 2, An interface between waste producers and the repository program is being implemented. 3. A series of tests has been started to evaluate the reactivity of fully radioactive glasses in a high-level waste repository environment mad compare it to the reactivity of synthetic glasses of similar composition. 4. The effect of radiation upon the durability of waste glasses at a high glass surface. _ea-tc)-liquid volume fSA/V) _ttio m3d higl_ gas-to-liquid volume ratio will be assessed. These tesLsaddress both vapor m_d high SA/V liquid conditions. 5. A series of test:_ is being performed to compare the extent of reaction (_t" nuclear waste glasses at various SA/V ratios, Such differences in the SA/V ratio may significantly affect glass durability. 6. An_ytical electron microscopy (AEM), infrared spectroscopy, and nuclear : resonant profiling are being used to assess the glass/water reaction pathway by identil'ying intermediate phases that appear on the reacting glass. Additionally, colloids trom the leach solutions are being studied using AEM.

High moisture content is a main characteristic of low-rank coal, such as lignite. Numerous oxygen containing functional groups in lignite make it represent some special properties, and these functional groups affect the adsorption mechanisms of water molecules on lignite surface. This study reports some typical water · · · lignite conformations, along with a detailed analysis of the geometry, electrostatic potential distribution, reduced density gradient of interaction, and interaction energy decomposition. The results show that water molecules tend to aggregate around functional groups, and hydrogen bonds play a dominant role in the interaction. The adsorption energy of water cluster on lignite surface is larger than that of isolated water molecule, a good linear relationship between the interaction distance and adsorption energy of layers has been found. Since water is a polar molecule, the local minima and maxima of electrostatic potential in conformations increase along with more water adsorbing on lignite surface. Reduced density gradient analysis shows that H-bonds, van der Waals interaction, and a little steric make up the interaction between water cluster and lignite molecule. In these studied conformations which mainly are H-bond complexes, electrostatic and exchange repulsion play a dominant role, whereas polarization and dispersion make relatively small contribution to the interaction. Attractive and repulsive interaction both affect the stability of water · · · lignite conformations.

Samples of fly ash were obtained from four boilers in China. The unburned carbon content, mercury concentrations, and mean ash particle size were measured. The ashes were heated at seven different temperatures, and the mercury released from the heated ashes was determined. The mercury species in the ashes were analyzed. The correlation between the mercury captured by ash and the carbon in ash was determined. The ratio of Hg to ash has an important role in particulate Hg formation. The high Cl content in coal does not absolutely result in the capture of more mercury by ash, but can result in high HgCl2 ratio in particulate mercury. The HgO ratios are low, and the HgSO4 ratios of all the ashes are negligible. The sulfur in coal is an important factor in the sorption of mercury by fly ash, and the high S content in coal results in a high HgS ratio in ash. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 460–467, 2017

Many ways may be available to transport the hazardous materials. However, different ways will lead to the difference in the cost of transportation and loss of total social expectations. Under the same condition, this paper studies the best way and path to move the materials of danger. It explains the solving method of the model by a simulation example. The comparison of the various ways of transportation shows that a combination of different ways can lower the cost of the transportation as well as the loss of the total social expectations.

Density functional theory calculations were performed to gain insight into the mechanism and kinetic studies of homogeneous gas-phase formation of polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD/Fs) via aliphatic hydrocarbons (CH, CH, CH and CH). The calculated results demonstrated that the intra-annular elimination of H is the rate-determining step throughout the reaction chain; the presence of ortho-Cl increases the abstraction barrier of arene H and decreases the reactivity of the molecule. The phenoxy radicals undergoes dimerization via carbon-carbon or carbon-oxygen coupling to form PCDD/Fs and the two coupling pathways are competitive. Our work indicates that aliphatic hydrocarbons are less reactive precursors in PCDD/F formation compared with chlorophenoxy radicals and phenoxy radicals among primary precursors of PCDD/Fs. The results presented here could be used to evaluate the contribution of aliphatic hydrocarbons acting as precursors to PCDD/Fs formation.